1. Field of the Invention
The invention relates to machine stands and more particularly to a bracket assembly and a retaining device for a collapsible stand for supporting a machine (e.g., circular sawing machine).
2. Description of Related Art
U.S. Publication Number 2006/0272744 to Liu et al. discloses a bracket assembly for a mobile stand having a long beam and a plurality of legs that support the long beam for supporting a machine, the bracket assembly comprising a bracket body mountable on the long beam of the mobile stand; a front clamp mounted in the bracket body, the front clamp having a front stop face contactable with the long beam of the mobile stand; a rear clamp pivoted to the bracket body and corresponding to the front clamp, the rear clamp having a rear stop face contactable with the long beam of the mobile stand, and a guide face opposite to the rear stop face; and a locking control device having an eccentric member and a follower rotatably coupled to the eccentric member, the eccentric member being pivoted to the bracket body and having an operating handle extending out of the bracket body, the follower having a push face kept in contact with the guide face of the rear clamp.
However, when the bracket assembly is mounted on a power tool, an upward or downward of the handle offers a little cam force to the long beam in operation. Thus, the long beam may hit the handle accidentally if the handle is not secured and the handle pivots upward or downward. This is very dangerous especially in cutting.
U.S. Pat. No. 8,528,870 to Liu et al. discloses a retaining device for a stand having a drawable extending rod, the retaining device comprising a base having a through hole for penetration of the extending rod; a shaft inserted in the base; a handle having a cam portion and an eccentric hole through the cam portion, and pivotally mounted on the shaft through the eccentric hole; a retainer moveably mounted in the base and having a receiving hole in which the cam portion of the handle is received such that the retainer is moveable by a pivotal movement of the cam portion of the handle to stop the extending rod in position; and an adjustment unit including the shaft having an eccentric shaft portion passing through the eccentric hole of the handle, and a teeth portion at an end of the eccentric shaft portion, a screw inserted in the shaft and provided with a distal end passing through a retaining hole of the base, a nut screwed to the distal end of the screw, and an elastic member sleeved on the screw and stopped against the base and the shaft; wherein when the screw is tightened, the teeth portion of the shaft is engaged with a teeth hole of the base for preventing the shaft from rotation, and when the screw is loosened, the teeth portion of the shaft is disengaged from the teeth hole of the base by an elastic force of the elastic member for allowing the shaft to be rotatable.
However, an upward or downward of the handle offers a little cam force to the long beam in operation and its positioning effect is poor. Thus, the extending rod may be vibrated by the cam in an urging action. And in turn, it may adversely affect the safety in a cutting operation. Thus, the long beam may hit the handle accidentally if the handle is not secured and the handle pivots upward or downward. This is very dangerous especially in cutting.
Notwithstanding the prior art, the invention is neither taught nor rendered obvious thereby.